2,2'-[6-(4-methoxyphenyl)-1,3,5-triazine-2,4-diyl]bis{5-[(2-ethylhexyl)oxy]phenol}

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3 July 2002 to 26 Sept 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Objective of study:

absorption

distribution

excretion

metabolism

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Radiolabelling:

yes

Remarks:

14-C

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Alpk:APfSD

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Biological Services Section, Alderley Park, Macclesfield, Cheshire
- Age at study initiation: no data
- Weight at study initiation: 254 - 286 (mean 272) grams for males; 224 - 254 (mean 239) grams for females
- Fasting period before study: no
- Housing: individual stainless steel metabolism cages (for excretion / distribution study) & stock cages for blood sampling study
- Individual metabolism cages: yes
- Diet (e.g. ad libitum): Rat and Mouse #1 maintenance diet; Special Diet Services, Stepfield, Whitham; ad libitum
- Water (e.g. ad libitum): tap, ad libitum
- Acclimation period: 4 days (stock cages), 1 day (metabolism cage)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +- 3
- Humidity (%): 30 - 70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Remarks:

PEG 400

Details on exposure:

Dose preparation
The dose preparation was formulated as a suspension and comprised unlabelled CGF-C1607 and [14C]-radiolabelled CGF-C1607 homogeneously dispersed in the dose vehicle PEG 400. Unlabelled and radiolabelled CGF-C1607 were mixed and milled to a particle size comparable to that ofthe unlabelled CGF-C1607 supplied (nominally 10 µm) prior to dose preparation.
Concentration (unlabelled and radiolabelled CGF-C1607) in the dose preparation: 11.0 mg CGF-C1607/g.
Specific activity in the dose preparation: 103.4 kBq/mg.
When administered at a nominal dose level of 4 ml/kg, this represented a nominal dose level of 50 mg/kg and a mean radiochemical dose of 5.11 MBq/kg.

The mean achieved dose was 49.4 mg/kg, which was 98.9% ofthe intended dose of 50 mg/kg.

Duration and frequency of treatment / exposure:

Single dose

Doses / concentrations

Dose / conc.:

50 mg/kg bw/day (nominal)

Remarks:

mean achieved dose was 49.4 mg/kg

No. of animals per sex per dose / concentration:

4 (for mass balance study)
9 (for blood sampling study)

Control animals:

no

Positive control reference chemical:

Not applicable

Details on dosing and sampling:

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
Tissues and body fluids sampled:
Mass balance study: For rats 1-8, urine and faeces were collected and the following whole tissues were removed: brain, spleen, liver, kidneys, pituitary, thymus, adrenal glands, testes and epididymis or ovaries, uterus and mammary tissue as appropriate, together with a representative sample of peri-renal adipose tissue (fat). The gastrointestinal tract including contents was removed.
Blood sampling study: For rats 9-26, serial blood samples were collected.

Time and frequency of sampling:
Mass balance study:For rats 1-8, urine and faeces were collected 24, 48, 72 and 96 hours after dosing and were terminated 96 hours after dosing. Following removal of each rat, the metabolism cages were washed with ethanol : water (1:1 v/v). Terminal blood sample were taken by cardiac puncture and divided between two pre-weighed heparinised tubes, which were weighed as a pair before one was centrifuged to separate plasma.
Blood sampling study: For rats 9-26, serial blood samples were collected by tail venepuncture at 1, 2, 4, 6, 8 and 10 hours after dosing and were terminated 12, 18 or 24 hours after dosing at which time terminal blood samples were taken by cardiac puncture.

Termination method: Each rat was killed by exsanguination under terminal anaesthesia, using Halothane Ph Eur vapour.

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: faeces
- Time and frequency of sampling: 0-24 hours, 24-48 hours, 48-72 hours, and 72-96 hours
- From how many animals: 4 males & 4 females
- Method type(s) for identification: HPLC-MS using a Finnigan MAT LCQ ion trap mass spectrometer equipped with an electrospray source.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Measurements in blood and plasma at intervals of 1-24 hours after dosing indicated that there was very little absorption of CGF-C 1607 from the gastrointestinal tract. The concentration of radioactivity in the blood and plasma was below the limit of detection at all time points, and therefore it is not possible to calculate Cmax, T1/2 or AUC values. The mean limits of detection were <0.038 µg/g and <0.019 µg/g in blood and plasma respectively.

Details on distribution in tissues:

No pronounced sex difference in the tissue distribution of radioactivity was found 96 hours after dosing.
Residues in the tissues were very low and residues were not associated with any specific tissues.
Residues in tissues accounted for <0.01% of the dose in total (males and females).
The mean radioactivity remaining in the residual carcass accounted for 0.26% (males) and 0.10% (females).

Details on excretion:

Excretion was rapid and extensive in both male and female rats.
Over 96 hours, the mean total proportions of administered radioactivity excreted in urine and faeces (incl. terminal cage wash) were 95% for males and 97% for females.
Compared to the mean content found in urine (0.1-0.2%), the vast majority of radioactivity was excreted via feces (94-97%).
Residual radioactivity in the gastrointestinal tract and contents (<0.04% and <0.02% in males and females, respectively) confirms, that faecal excretion was complete by 96 hours.

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

Parent CGF-C1607 was the only component found in the faecal extracts. Therefore, unchanged CGF-C1607 represented 100% of the dose excreted in faeces in both male and female rats.

Any other information on results incl. tables

Analytical results

Radiochemical purity was 98.4% (stock solution), 97.8% (dose preparation). These small differences in the radiochemical purity were not considered to be relevant.

Stability analyses of [14C]-CGF-C1607 in both dose preparations demonstrated, that the test substance was stable beyond the periods of use in this study.

Exclusion of data

A low recovery (82.7%) was obtained for 1 female rat in the mass balance study and therefore, the data for this animal have been excluded from the calculated mean results.

Summary of the recovery of radioactivity following a single oral dose of 50 mg/kg bw in % of applied dose (SD)

Excreta/ Tissues	Male (n=4)	Female (n=3)
Urine	0.13 (0.07)	0.21 (0.18)
Faeces	94.32 (3.98)	96.61 (2.01)
Cage Wash	0.09 (0.09)	0.15 (0.13)
GI Tract + Contents	<0.04	<0.02
Tissues + Carcass	0.27 (0.08)	0.11 (0.07)
Total	94.85 (3.74)	97.08 (1 .64)

Applicant's summary and conclusion

Executive summary:

Groups of 4 male and 4 female rats were each given a single oral dose of 50 mg [14C]-CGF-C1607/kg to investigate systemic exposure, tissue distribution and metabolite profiles. The excretion of radioactivity in urine and faeces was monitored for 4 days after dosing. After this period, the rats were killed and residual radioactivity was measured in blood, selected tissues and the remaining carcasses. An additional group of 9 male and 9 female rats were each given a single oral dose of 50 mg [14C]-CGF-C1607/kg and radioactivity was measured in blood and plasma over a 24 hour time course after dosing.

 

Excretion was rapid and extensive in both male and female rats. Urinary excretion accounted for mean totals of 0.1% and 0.2% of the dose and faecal excretion accounted for mean totals of 94% and 97% of the dose for males and females respectively. The only component in the faecal extracts was identified as the parent compound CGF-C1607. Therefore, unchanged CGF-C1607 represented all of the dose excreted in faeces. Residues in the tissues were very low and accounted for <0.01% of the dose in total in both males and females. The mean radioactivity remaining in the residual carcass accounted for 0.3% of the dose for males and 0.1% for females. The total recoveries of administered radioactivity were approximately 95% for males and 97% for females. The concentration of radioactivity in blood and plasma was below the limit of detection at all time points up to 24 hours after dosing.

 

In conclusion, following a single oral dose of 50 mg [14C]- CGF-C1607/kg to male and female rats, the excretion was rapid in both sexes, with 94-97% of the administered dose excreted directly in faeces within 96 hours as unchanged CGF-C1607. This is consistent with the measured concentrations of radioactivity in blood and plasma of less than the limit of detection over a 24 hour time course after dosing. Quantitatively, no sex difference was observed. Urinary excretion accounted for 0.1-0.2% of the dose, and residual radioactivity in tissues and carcass accounted for 0.1-0.3% of the dose. Residues in individual tissues were all <0.01 % of the dose. Following oral dosing, it is considered that absorption of [14C]- CGF-C1607 was very low.